1. Field of the Invention
The field of this invention relates to flashlights and other portable lighting devices, which are used in the home (inside and outside), in automobiles, for personal safety and emergency uses, for camping and recreation, for construction, for law enforcement uses, etc. More specifically, this invention relates to flashlights and other portable lights that have a charging mechanism and a power storing mechanism, wherein there is no need for batteries.
2. Discussion of Related Art
Ordinary flashlights and portable lights have been in use for many years throughout the world. The most popular kinds of flashlights and portable lights use disposable batteries and replaceable light bulbs. There are also a number of portable lights available today that contain rechargeable batteries, typically used in connection with home recharging units in which plugging the light into an ordinary home electrical outlet will charge the batteries. However, eventually these kinds of portable lights need new batteries, as the rechargeable batteries become depleted and incapable of holding a charge after extensive use.
There would be many advantages in having a portable light that never needs a change of batteries, never needs a bulb replacement, and can be very quickly charged from a power source. The applications for such a light include inside and outside home use, automobiles emergency use, camping, bicycling, general emergency use, construction and law enforcement uses, and numerous uses in underdeveloped countries. Such a light would also represent an economic and ecological advantage in reversing the environmental impact of discarded batteries, such as nickel-cadmium batteries; the most commonly used, highly toxic, rechargeable battery.
The most popular flashlights and portable lights used in the world today are described in U.S. Pat. Nos. 4,032,773, U.S. Pat. No. 4,041,304, U.S. Pat. No. 4,151,583 and closely related prior art. These flashlights have one or more disposable batteries, a single on/off switch, and a light bulb backed by a reflective cone and covered with a glass or plastic lens. The major problem with these types of flashlights is that the battery charge decays with use and the batteries must be replaced regularly. This is costly, inconvenient, and has a negative environmental impact. In addition, the bulbs burn out and require replacement costs and wasted time in locating new bulbs.
Rechargeable flashlights and portable lights have been described in several United States patents, including: U.S. Pat. No. 3,787,678; U.S. Pat. No. 3,829,676; U.S. Pat. No. 4,045,663; U.S. Pat. No. 4,819,139; U.S. Pat. No. 4,794,315; U.S. Pat. No. 4,325,107; and U.S. Pat. No. 4,357,648. The portable lights disclosed in these patents have rechargeable batteries that last many times longer than the typical disposable batteries in typical flashlights. However, the principal problem with rechargeable battery flashlights is that the rechargeable batteries wear out and must be replaced, and these batteries, which are often nickel-cadmium batteries, pose dangerous problems to the environment if not disposed of properly. Another problem with this type of portable light is that recharging requires a lengthy amount of time.
Other portable lights using solar cells for charging the batteries have been described in U.S. Pat. No. 5,621,303, and EP 5,3143,8A1. The devices disclosed therein use rechargeable batteries that wear out and require replacement.
A portable light with a hand-crank generator has been described in U.S. Pat. No. 4,360,860. This light also has the problem of the rechargeable battery needing replacement at some time.
U.S. Pat. No. 5,782,552 describes a light used for highway signaling purposes, which employs a solar panel for charging, a capacitor for electrical storage and a blinking LED for the signal light. This patent describes a specific circuit for charging the capacitor when light is available and automatically energizing the blinking LED when ambient light is below a pre-determined level, and a means to stop energizing the LED when the ambient light is above a pre-determined level. This art does not describe the use of a bright-white LED (non blinking), which is used in the present invention for the source of light. In addition, the '552 patent makes no reference and provides no means of using the system for flashlights, portable lighting for home, recreation, automobile or emergency uses.
U.S. Pat. No. 5,975,714 describes a rechargeable flashlight using a capacitor for energy storage, an LED for light, and a linear motion generator to generate the power that is stored in the capacitor. This portable light has several problems. First, it uses a small Farad super capacitor, (1 Farad), which holds enough power for only about 5 minutes of light. Secondly, this portable light provides no other means, other than the shaking, to charge the capacitor. One final problem with the '714 is that the light intensity fades quickly; it starts out at full brightness, within two to three minutes it is at approximately half brightness, and it continues to fade.